Startup control valve for a dishwasher pump



April 2, 196s M'. D. SCHUTTE STARTUP CONTROL VALVE FOR A DISHWASHER PUMP Filed July 28, 1965 FIGJ- WITNESSES I2 Flea.

ATTORNEY United States Patent O ice ABSTRACT OF THE DISCLOSURE A dishwasher having a hot cleaning fiuid spray device, a conduit for supplying the spray device with yhot cleaning fiuid and a valve for slowing initial supply `of hot cleaning uid to the spray device to slow the heating of the relatively cool air admitted to the washer when previously open, ythereby avoiding dishwasherexplosion.

This invention relates to an improved control valve for retarding the initial flow of uid through a conduit at the startup of a pump, and more particularly to a control valve of the type described for use in automatic dishwashing machines.

As is known, automatic dishwashers employ very hot water for cleaning utensils such as dishes, `glasses and the like. The operation of the automatic dishwasher is divided `int-o a filling `cycle and a cleaning cycle. During the filling cycle, hot Water is introduced into the bottom of the cleaning chamber which mixes with a detergent previously placed therein, so as `to form a pool of waterdetergent solution or cleaning uid. When the water reaches a certain level, the filling cycle is complete and the cleaning cycle begins. At this time, -a pump recirculates the hot cleaning fluid through a conduit connected to a sprayer device which sprays the hot cleaning fluid over the utensils being cleaned. In most automatic dishwashers, `a safety switch is provided which interrupts the operation ofthe dishwasher whenever the door is opened.

The opening and closing of the door during the cleaning cycle may produce an explosion within the cleaning chamber. For example when the door of the dishwasher is opened during `the cleaning cycle, the hot aircontained therein is replaced by room air whose temperature is considerably below that of the hot air. When the door is again closed, the pump is :started and immediately the hot cleaningtfluid is sprayed into `the cold air. The sprays of hot cleaning uid heat the cold air rapidly resulting in a sudden rise of air pressure `Within the dishwasher. The pressure rise tends to break the gasket seal around the door and forces air out of any available opening. Since the air is expelled at `a relatively high velocity during the explosion, it entrains droplets ofthe cleaning fiuid 'which is `sprayed onto nearby objects, causing damage to the same.

The conventional method of controlling the explosion inside the dishwasher is to vent the dishwasher casing to the atmosphere. However, in order to reduce the velocity of the expelled air so that little or `no ycleaning fluid is entrained in the air stream, an extremely large Avent is required. The large vent, in turn, necessitates the use of a complicated baiiie to eliminate fluid `penetration-during the normal washing operation, a `flapper or damper to reduce loss ofhot air during the drying operation, and also louvers to remove vany `small amounts of entrained fiuid droplets from theexpelled air.

Accordingly, as Ian overall object, the present invention seeks to provide control meanstfor preventing an'rexplosion in `automatic dishwashers by retarding the initial flow of the hoftzfluid sprays so thatthe relatively cool air within the dishwater is heated slowly.

3,375,854 Patented Apr. 2 1968 Another object of the invention is to provide an improved control valve for retarding the initial fiow of hot fluid sprays whereby a relatively small vent opening 'in the dishwasher casing can adequately handle the expelled air at relatively low velocities. In this respect, it will be appreciated that low velocity air will not entrain fluid from within `the dishwasher.

Still another object of the invention is to provide a control valve which is completely automatic in operation and which offers no resistance to the flow of hot uid during normal operation of the dishwasher.

A further object of the invention is to provide a control valve having a minimum number of parts and which is relatively inexpensive to manufacture.

A still further object of the invention is to provide means for controlling the explosion normally encountered in a dishwasher during fast startups, which means eliminates the need for relatively large vent openings and their associated bafiies, fiappers and louvers as described above.

In accordance with lthe invention, a control valve is provided which is adapted to be installed in a supply conduit which communicates the hot cleaning fluid to a sprayer device. The control valve comprises a first iiapper disposed within the conduit and supported for pivotal movement from a first position wherein it opposes the fiow of hot fiuid through the conduit to a second position wherein the fiapper is positioned parallel to the flow of the `hot fluid and therefore offers substantially no resistance to its fiow.

Connected to the first flapper is a dashpot which is disposed externally of the sprayer supply conduit and is submerged beneath the surface of the pool of hot cleaning fluid provided in the bottom of the dish chamber during the filling cycle of an automaticdishwasher. The dashpot is `adapted to contain a portion of the cleaning fluid in which it is submerged and operates by displacement of the `cleaning fluid to retard the pivotal movement of the fiapper duringtits movement from the first position to the second position. The dashpot is arranged so that the return of the fiapper from the second position to the `first position is accomplished in a rapid manner. The overall arrangement is such that when the pump of a dishwasher is started, the `torce of the pressurized hot cleaning fluid will move the apper from the first position to ward the :second position. However, the dashpot retards this movement so `that the initial flow rate of lthe cleaning fluid is small and gradually increases. When the fiap- `per reaches the second position, the cleaning fiuid is permitted to flow freely at its rated capacity.

The above and other objects and advantages of the present invention will `become apparent from the following detailed description by reference to the accompanying drawings, in which:

FIGURE 1 is a side view, in cross section, schematicallv illustrating a conventional automatic dishwasher provided with the control valve of the present invention;

FIG. 2 is a cross-sectional View taken along the line II-II of FIG. l, illustrating the preferred embodiment of a dashpot lemployed in the present control valve;

FIG. 3 is a cross-sectional view taken along the line Ill- III of FIG. 1, illustrating a flow resisting portion of the present control valve;

FIG. 4 is a cross-sectional view taken along the line IV-IVof FIG. 2, illustrating the overall arrangement of the present control valve; and

FIG. 5 is a side View illustrating an alternative embodiment of the dashpot.

Referring `now to FIG. 1, there is schematically illustrated a conventional automatic dishwasher 10 comprising a casing 1'2 dening a cleaning chamber 14 into which the articles to be cleaned are introduced. The casing 12 is provided with a door 16 carrying a gasket 18 for sealing an opening in the casing 12. A fiuid distributing arm 22 is pivotally supported on the upper end of a tubular support conduit 24 positioned centrally of the bottom wall 26 of the casing 12.

In the bottom of the casing 12 there is a pool of hot cleaning uid 28 which, as explained above, is provided during the filling cycle of the dishwasher 10 and comprises a detergent-water solution. The supply conduit 24 projects upwardly through the pool of cleaning fluid 28 and communicates with a pump 30 driven by a motor 32, which recirculates the hot cleaning fluid through the supply conduit 24 into the fluid distributing arm 22. The fluid distributing arm 22 may, for example, comprise a selfpropelled sprayer pipe wherein the sprays of hot cleaning fiuid rotate the arm about a vertical axis coincident with the longitudinal axis of the support conduit 24. Suitable racks (not shown) normally are disposed above the iiuid distributing arm 22 and serve to support the utensils during cleaning thereof.

A safety switch schematically illustrated at 34, is normally positioned to be engaged by the door 16. The safety switch 34 serves to stop the motor 32 when the door 16 is opened and to start the motor 32 when the door 16 is closed. The casing 12, in accordance with the present invention, is provided with a relatively small vent opening 36 through which the relatively cool air within the cleaning chamber 14 is exhausted at the start of a cleaning operation or after the cleaning cycle has been restarted. A suitable baie 38 may be provided to prevent the hot cleaning fluid from being discharged through the vent opening 36 during the normal cleaning operation.

In accordance with the present invention, a control valve 40 is provided in the support conduit 24 and submerged within the pool of cleaning fiuid 28. The control valve 40 is arranged to retard the initial iiow of hot cleaning fiuid through the support conduit 24 only when the pump 30 has been restarted, i.e., during the cleaning operation, as will be described.

Referring now to FIGS. 2-4, the fiow control valve 40 comprises a fiow resisting portion 42 residing within the support conduit 24 and a dashpot 44 positioned externally of the support conduit 24 within the pool of hot cleaning fluid 28. The fiow resisting portion 42 preferably comprises a fiapper 46 secured along an edge 48 to a shaft 50 extending transversely through the support conduit 24 and rotatably supported by its side walls. The shaft 50 defines an axis about which the iiapper 46 is pivotal. As can best be seen in FIG. 4, the fiapper 46 is generally rectangular and conforms with the generally rectangular shape of the support conduit 24. Hence, the peripheral edges of the iiapper 46 are engaged with the inner surfaces of the support conduit 24, the arrangement being such that only minimal amount of hot cleaning fluid may flow between the side walls of the support conduit 24 and the peripheral edges of the iiapper 46.

As can best be seen in FIG. 3, the iiapper 46 is shown in full lines at an intermediate position. The flapper 46 being pivotal about the shaft 50 may be positioned at a first position A shown in dotted outline, where in the iiapper 46 extends transversely of the support conduit 24 and opposes the upward flow of the hot cleaning fluid; and a second position B indicated in dotted outline, wherein the fiapper 46 is positioned parallel with the upward fiow of the hot cleaning fluid and offers substantially no resistance to the upward flow of the hot cleaning fluid. As will be described, the tiapper 46 will be moved by the flow of hot cleaning fluid upwardly through the support conduit 24 from the position A to the position B at the start-up of the pump 30. When the pump 30 is stopped and the cleaning iiuid ceases to iiow upwardly through the support conduit 24, the apper 46 will fall from its position at B to its position at A.

As explained above, it is desirable to retard the flow of the hot cleaning fiuid through the support conduit 24 at the start-up of the pump 30 in order to prevent an eX- plosion within the cleaning chamber 14. To accomplish 4 this retardation, the dashpot 44 is provided which as can best be seen in FIGS. 2 and 4, preferably comprises a second flapper S2 secured along an edge 54 to the shaft Sti whereby the first iiapper 46 and the second fiapper 52 will pivot in unison about the axis defined by the shaft 50. Means, 4preferably comprising a hood 56, is provided for enclosing the face 58 of the second flapper 52. The hood 56 and the second flapper 52 cooperate to define a variable volume compartment 60.

The hood 56 comprises three fiat side walls 62 and an arcuate side wall 64 whose radius of curvature corre sponds to the arcuate path of travel of the outer edge 66 of the second flapper 52. In FIG. 2, the second flapper' 52 is shown at an intermediate position. The second iiapper 52 being pivotal about the shaft 50, may be positioned at a first position A indicated in dotted outline, wherein it engages a stop member 68 which prevents further downward pivoting of the second flapper 52 and the first flapper 46; and at a second position B indicated in dotted outline, wherein it is vertical. In this arrangement, the first and second positions A, B of the second flapper 52 correspond to the first and second positions A, B of the first flapper 46. It should be evident, however, that other arrangements are possible wherein the first and second fiappers 46, 52 are angularly spaced from one another rather than being coplanar as specifically shown in the drawings. The second fiapper 52 is provided with an enlarged opening 70 which permits rapid passage of the cleaning fluid 28 between the compartment 60 and the pool of cleaning fiuid 28, as will be described. Overlying the enlarged opening 70 and secured to the face 5S of the second apper 52 is a resilient ta'b or leaf spring 72 provided with an opening 74 which is relatively small compared to the enlarged opening 70. The opening 74 permits only restricted flow of the cleaning iiuid between the variable volume compartment 60 and the pool of cleaning iiuid 28, as will be described. The leaf spring 72 is preferably secured along one of its edges so that it may -be lifted upwardly by the cleaning iiuid fiowing through the opening 70 into the dotted outline position shown in FIG. 2, during movement of the second apper 52 from the second position B to the first position A.

The enlarged opening 70 and the leaf spring 72 with its small opening 74 serve as variable orifice means permitting restricted iiow of iiuid through the small opening 74 in one direction of movement of the second apper 52 and substantially unrestricted iiow of fiuid through the enlarged opening 70 in the opposite direction of movement of the second flapper 52. As illustrated in FIGS. 2 4, the movement of the second apper 52 from the first position A toward the second position B will be retarded by the restricted iiow of the cleaning fluid through the small opening 74. When the hot cleaning fiuid ceases to tiow, the first fiapper 46 will pivot by means of gravity toward the first position A. During this movement, the leaf spring 72 will be displaced by the fluid iioWing through the enlarged opening 70 into the position shown in dotted outline in FIG. 2, so that the fiow of fluid will be substantially unhindered. Hence, the first and second flap-pers 46, 52 return to their first position A in a rapid manner. If desired, a spring may be employed for quickly returning the iiappers 46, 52 to the position A.

An alternative embodiment of the dashpot is illusv trated in FIG. 5 and kindicated generally by the numeral 80. Corresponding numerals will be employed to identify corresponding parts heretofore described.

In this embodiment, the dashpot comprises a first plate member 82 secured to the Support conduit 24; a second plate member 84 secured to the shaft 50 for pivotal movement about the axis defined thereby; and a resilient bellows 86 having a rst end y88 secured to the first plate member 82 and a second end 90 secured to the second plate member 84. The interior of the resilient bellows S6 comprises a variable volume compartment 92. The second plate member 84 is provided with the enlarged opening 70 and has secured to its inner face the leaf spring 72 which includes the small opening 74. The operation of the dashpot 80 is identical with the operation of the dashpot 44 described above.

Although the invention has been shown in connection with certain specific embodiments, it will be readily apparent to those skilled in the art that various changes in form and arrangement of parts may be made to Suit requirements without departing from the spirit and scope of the invention.

I claim as my invention:

1. In a dishwasher, the combination of a cleaning charnber, a sprayer device within the chamber for spraying hot cleaning fluid under pressure onto articles within the chamber, a conduit for supplying hot cleaning fluid under e pressure to said sprayer device, a vent opening in said cleanin-g chamber for expelling air under pressure from the chamber, and valve means for retarding the rate of flow of said hot cleaning uid to the sprayer device at the start of a cleaning operation, said valve means cornprising a flow resisting member supported in Said conduit -for pivotal movement from a first position in which said member opposes the flow of -hot cleaning Huid to a second position wherein said member offers substantially no resistance to the flow of said hot cleaninguid, and dashpot means disposed externally of said support conduit and connected to said ow resisting member for retarding the pivotal movement thereof from said first position to said second position, whereby the rate of spraying said hot cleaning fluid increases slowly from a minimum value to a maximum value to slowly heat the air in said cleaning chamber and expel it through said vent opening at a relatively low velocity.

2. In a dishwasher of the type having a cleaning chamber and a pool of hot cleaning fluid in the bottom of the cleaning chamber, the combination of a tubular support extending through the bottom of said cleaning chamber and having an upper end above the level of said pool of hot cleaning fluid, sprayer means mounted on the upper end of said tubular support for spraying hot cleaning fluid into the interior of said cleaning chamber, means for supplying hot cleaning fiuid under pressure to said tubular support, a small vent opening in said cleaning chamber for venting air contained therein, and valve means for retarding the rate of ow of said hot cleaning fiuid through said tubular support at the start of a cleaning operation, said valve means comprising a flow resisting member supported in said tubular support for pivotal movement from a first position in which said member` opposes the flow of hot cleaning fiuid to a Second pos1- tion wherein said member offers substantially no resistance to the flow of said hot cleaning fluid, and dashpot means disposed externally of said tubular support and connected to said ow resisting member for retarding the pivotal movement thereof from said first position to said second position whereby the rate of spraying said hot cleaning fluid increases slowly from a minimum value to a maximum value, the dashpot means being `disposed beneath the level of said pool of cleaning fiuid and including a fiapper connected to the fiow resisting member for pivotal movement therewith, means enclosing a face of said iiapper and defining a variable volume compartment which varies in volume as the apper rotates with said flow resisting member between its first posi` tion and its second position, and orifice means in said fiapper for restricting the flow of said cleaning iiuid between said variable volume compartment and said pool of cleaning fluid during the movement of said flow resisting member toward said second position.

3. The combination of claim 2 including second orifice means in said iiapper for permitting substantially unrestricted flow of said hot cleaning fluid between said variable volume compartment and said pool of hot cleaning fiuid during movementof said fiow restricting member toward said first position.

pressure to said tubular support, a small vent opening in said cleaning chamber for venting air contained there-j in, and valve means for retarding the rate of fiow of sai-d hot cleaning fluid through said tubular support at the start of a cleaning operation, said valve means comprising a first fiapper disposed within said tubular support below the level of said pool of hot cleaning fiuid and supported for pivotal movement about an axis extending transversely of said tubular support, said first fiapper being pivotal about said axis from a first position in which it opposes the fiow of said cleaning fluid through said tubular support to a second position in which it offers substantially no resistance to the flow of said hot cleaning fluid through said tubular support, a second dapper disposed externally of said tubular support and within said pool of hot cleaning fluid, means connecting said second flapper to said first apper for pivotal movement therewith about said axis, means enclosing one face of saidl second fiapper for defining a variable volume compartment which varies in volume as the second fiapper `pivots with said first fiappper between its first position and its second position, and orifice means in said second flapper for restricting the iiow of said hot cleaning fiuid between said variable volume compartment and said pool of hot cleaning fiuid during movement of said flow resisting member toward said second position.

5. The combination of claim 4 wherein said means for enclosing one face of said second fiapper comprises a stationary hood having side walls engaged with the peripheral edges of said second flapper, the side Wall remote from said axis being arcuate and having a radius of curvature corresponding to the radius of curvature of the arcuate path of travel ofthe apper edge engaged therewith.

6. The combination of claim 4 wherein said means for enclosing one face of said second flapper comprises a bellows extending between a stationary plate and said second flapper.

7. In a dishwasher of the type having a cleaning chamber and a pool of hot cleaning fluid in the bottom of the cleaning chamber, the combination of a tubular support extending through the bottom of said cleaning chamber and having an upper end above the level of said pool of hot cleaning fluid, sprayer means mounted on the upper end of said tubular support for spraying said hot cleaning fiuid into the interior of said cleaning chamber, means for supplying hot cleaning fluid under pressure to said tubular support, a small vent opening in `said cleaning chamber for venting air contained therein, and valve means for retarding the rate of flow of said cleaning fluid through said tubular support at the start of a cleaning operation, `said valve means comprising a first flapper positioned within said tubular support below the level of said rpool of cleaning fiud, a second flapper positioned externally of said tubular support and 'within said pool of cleaning uid, a shaft extending through said tubular support and rotatably supported therein, said first flapper and said second fiapper being secured to said shaft along their aligned edges and being pivotal in unison therewith, said first apper being pivotal from a first position wherein it opposes the flow of said cleaning fiuid to a second position wherein it offers substantially no resistance to the ow of said cleaning Huid, means enclosing one face of said second fiapper for defining a variable volume compartment which varies in volume as the second fiapper pivots with said first iiapper between its first position and its second position, rst orifice means in said second flapper for restricting the flow of said cleaning fluid between said compartment and said pool of cleaning fluid during movement of said first flapper toward said second position, and second orifice means in said second flapper for permitting substantially unrestricted flow of said cleaning fluid between said compartment and said pool of cleaning fluid during movement of said first flapper toward said first position.

8. In a dishwasher of the type having a cleaning chamber and a pool of hot cleaning fluid in the bottom of the cleaning chamber, the combination of a tubular support extending through the bottom of said cleaning chamber and having an upper end above the level of said pool of hot cleaning fluid, sprayer means mounted on the upper end of said tubular support for spraying said hot cleaning fluid into the interior of said cleaning chamber, means for supplying hot cleaning fluid under pressure to said tubular support, a small vent opening in sa-id cleaning chamber for venting air contained therein, land valve means for retarding the rate of flow of said cleaning fiuid through said tubular support at the start of a cleaning operation, said valve means comprising a first flapper positioned within said tubular support below the level of said pool of cleaning fluid; a second flapper positioned externally of said tubular support and within said pool of cleaning fluid, a shaft extending through said tubular support and rotatably supported therein, said first flapper and said second flapper being secured to said shaft along their aligned edges and being pivotal in unison therewith, said first flapper being pivotal from a first position wherein it opposes the flow of said cleaning fluid to a second position wherein it offers substantially no resistance to the flow of said cleaning fluid, means enclosing one face of said second flapper for defining a variable volume compartment which varies in volume as the second flapper pivots with said first flapper between its first position and its second position, said second flapper having an enlarged opening therein permitting substantially unrestricted flow of said cleaning fluid between said compartment and said pool of cleaning fluid during movement of said first apper toward said first position, a resilient tab secured to said second flapper and overlying said enlarged opening, and said resilient tab having an aperture whose cross-sectional area is small compared to the cross-sectional area of said enlarged opening, said aperture permitting restricted flow of said cleaning fluid between said compartment and said pool of cleaning fluid `during movement of said first flapper toward said second position.

References Cited UNITED STATES PATENTS 2/1914 Wood 137-514 2/1952 Vars 134-182 X 

